Thermostat remote control



June 20, 1939. H- WAAGE 2,163,297

THERMOSTAT REMOTE CONTROL Filed Aug. 10, 1937 L? m AAAA/AAAAAAAA 2 /9. t I vvvvvvvvvvvvv fi/4 INVENTOR.

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Patented June 20, 1939 I UNITED STATES PATENT; OFFICE THERMOSTAT REMOTE CONTROL Alvin H. Waage, Westfleld, N. J.

vApplication August 10, 1937, Serial No. 158.291

' 4 Claims. (01. 219-29) The purpose of this invention is to provide means for breaking or controlling the circuit to a heated body or other device, in which the device may be located at a remote point from the body,

5 and thereby not affected by the temperature of said heated body.

The invention is the use of a short section or strand of high positive temperature coemcient I metal connected in series with or to the element of a heated body or device, and this strand of metal is connected through a variable resistance coil surrounding a section of the bimetal of a thermostat, or to a relay, or the like, so that as the temperature of the heated body or device heats the strand of metal, having a high temperature coeflicient, it will build up suflicient potential difierence to regulate or control current, indicate temperature or break a circuit.

In heating objects with electric heating elements in which it is desired to incorporate a thermostat to break the circuit at a predetermined temperature, the thermostat is incorporated in the object so that it is affected by the high temperature thereof, and the life thereof is relatively," short, whereas, if the thermostat can be located at a remote point where it is subjected only to atmos-' pheric temperature, the life and operation thereoi will be increased and improved.

One object of this invention is, therefore, to 80 provide means to operate a thermostat to break or control a circuit by the temperature of a heated body with the thermostat situated at a remote point.

Another object is to provide a method of incorporating a metal having a relatively high temperature coeflicient in a heated body, so that it may build up sumcient force at a remote point to operate a thermostat or circuit controlling or indicating device. 40 A further object is to provide a relatively small section of high temperature coeflicient metal in a heated body, for operating a control device of a circuit to said body, in which the temperature of said body may be controlled through said device. And a still further object is to provide a device for operating a circuit controlling device or an electrically heated body situated at a remote point from said body, which is of a simple and economical construction.

With these ends in view the invention embodies a section or high temperature coemcient metal in combination with a heating element or device, and

connected in series to operate to control, indicate,

or break a circuit, and means adjusting the oper- BI ating temperature of said device.

Other features and advantages of the invention will appear from the following description taken in connection with the drawing, wherein:

Figure 1 is a diagrammatic view showing the operating circuit as it may be used-in an electric 5 iron, with the iron indicated by dotted lines.

Figure 2 is a view showing a similar circuit of an alternate design in which the high temperature coefiicient metal is provided as a separate unit,

and the controlling circuit is provided with an 10 adjustable resistance.

Figure 3 shows an alternate arrangement, in which the device forms a separate unit that may be used independently andattached or connected to any device, and in this design a relay is used as 15 the controlling element.

Figure 4 also shows a similar device in which the thermostat is provided with adjusting means.

In the drawing the device is shown as it may be made, wherein numeral i indicates an electric o heating element, numeral 2, a bimetal strip of a thermostat, numeral 3, a coil oi an adjustable resistance, and numeral 4, a strand of metal having a high temperature coefllcient and being positive in all designs. g 25 One terminal 5 o! the element i may be connected through a wire 8 to a source of current supply, and the other terminal I may be connected to the source of supply through a wire 8 passing through the thermostat 2, and a wire 9 as shown. 30

The strand 4 which has a high temperature ooemcient is connected to the element between the points I and ill, and through a terminal ii,

and a wire I! to a coil i3, around the bimetal element 2, with the end of the coil l3 attached 35 to a contact point i4, and this contact point engages another contact point I! on a lower section ii of the thermostat, completing the circuit from the strand 4 through the member 2 and the wire 8. In this design the position of the contact members or the thermostat may be adjusted by a screw H, in a base member l8, attached to the thermostat through insulating blocks 19 and 20. It will be understood, however, that these members may be adjusted in any 45 manner or by any means.

with these parts connected in this manner, and with a suitable voltage applied through the wires 6 and 9, the combined resistance oi! the parts I and 4 will cause the iron or device to be- 50 come heated, and, as the change in temperature occurs, the resistance of the heating coil I remains substantially constant whereas the resistance oi the part I is variable, increasing rapidly as the temperature increases, and, as this 70 1 point 21 so that the original circuit will be comresistance increases, the potential difierence between the points i and ill increases; causing an increase of energy in the thermostat winding i3. This produces heat in the member 2, and this heat, which is low as compared to the body of the iron, causes the bimetal to change shape and break the contact between the points i4 and i5.

With this break in the circuit the heat is instantly cut ofl in the coil i3, which permits the bimetal to cool quickly and the contact between the points i4 and i5 is resumed, thereby causing heat to accumulate in the iron or device again. This, in turn, builds up heat in the coil i3, thus continuing the cycle at substantially constant temperature or at a desired temperature.

This device may be located in the handle of an electric iron and provided with an adjusting screw ll or an eccentric cam so that the position of the member It may readily be-adjusted to obtain substantially any temperature desired.

The design shown in Figure 2 is similar to that shown in Figure 1, except that a wire 2i, similar to the wire i2, from the member 22, similar to the member 4 and which is shown as a separate coil, passes through an adjustable resistance 3, from which it is connected to the thermostat coil through a wire 23.

In the design shown in Figures 3 and 4, the device is shown as a separate and independent unit which may be incorporated in a cord of an electric appliance and used independently, or connected or attached to an appliance or device in any manner, or used in combination with any object or device; in which it may be desired to regulate, indicate, or shut off the current.

In the design shown in Figure 3, the metal or alloy having the high temperature coefllcient is indicated by the numeral 24, and this is connected in a circuit with an adjustable resistance 25 and a relay formed with contact points 26 and 27 and an electromagnet 28, and the current may be supplied through wires 23 and 30, with a plug or receptacle 3! which may be placed over'the terminals of an electric iron or other appliance. It will be noted that, as the current is applied, it will normally pass from the wire 39 directly to the receptacle, and from the wire 29 through the points 26 and 21, and the wire 32 to the high .mined amount, it will send sufilcient E. M. F.

through the wire 34 and the variable resistor 25 to energize the magnet 28, and this will raise the contact point 26 and break the circuit. When this movement takes place, a contact point 35 on the member 26 will engage a contact point 36, and this will send enough current through the wire 33 and the resistance 38 to form'a completed.

circuit tothe receptacle 3!, although the resistance 38 will check the amount of current, permitting the iron or other appliance to cool until an arm 39 of a thermostatic switch, which has been held upward by the heat of the element 24, to drop downward so that a contact point 40 will engage a point 4! and complete a circuit through the wire 42 and resistance 43 to the wire 30, thereby by-passing the magnet 28 which will permit the point 26 to drop and contact the pleted. It is appreciated that the changes in the temperature of the element 24 will not be exactly the same as the changes in the temperature of the appliance, however, the difierence is very slight, and the resistor 25 may be set to compensate tor the diflerence, and, in fact, by adjusting the resistor 25, it is possible to hold the temperature of an iron or other appliance ata substantially constant point.

In the design shown in Figure 4 the high temperature coefiicient metal 44 is connected in series with the thermostat 2, and the adjustable resistance 3 is positioned between the thermostat and the receptacle 45. In this design the thermostat may be adjusted by a screw 46 as shown, and by using both the means for adjusting the thermostat and theadjustable'resistance a wide range in regulation can be obtained, and this will be sufficient to compensate for the differences between the variations in the temperatures of an iron or other appliance and those of the element 44. In this design, thewires 41 and 48 are connected to a source of. electric current, and the receptacle or plug 45 may be plugged into an electric iron or other appliance, or this receptacle may receive-a plug at the end of an iron cord or the like. The wire 41 is connected directly to a terminal of the receptacle, and the wire 48 is connected to a member 49 of the switch in which the points 50 and Si are normally in contact, and are only separated when the resistance in the element 44 builds up sufliciently to raise the temperature in a thermostat 2, so that it will open the contact points 50 and 5|. The point 5! is connected by a wire 52 to the element 44, and the opposite end of the element is connected by a wire 53 to the receptacle. The wire 53 is also connected by a wire 54 to the variable resistance 3, and this is connected by a wire 55 to the coil of the thermostat.

It will be understood that other changes may be made in the process without departing from the spirit of the invention. One of said changes may be in the use of a circuit breaker, controller, or indicator or any other type, in place of the thermostat, another may be in the use of any other means for adjusting the temperature at which the device operates, andstill another may be in the use of any other means for connecting the various parts.

The construction will be readily understood from the foregoing description. In use the device may be installed as shown and described, and it will be understood that it may be used in, or in connection with, any heated body, and the parts may be located at any suitable point or points. When used in an electriciron, the heat temperature 'coefiicient. This high temperature 1 'coefiicient metal may be part of the element or a separate unit which can be connected in series with the element and held in contact with the body to be heated so that it will respond to th temperature of same.

The resistance of the high temperature coeflicient metal will increase with heat and thereseries with the thermostat coil, so that the heat can be controlled by adjusting the resistance.

This method of control makes it possible to locate the thermostat where most convenient and so that it can be operated in very low temperatures which means that its life will be much greater than it it were working under the high temperature of the heated body.

The current to operate the thermostat is obtained by the voltage across the high temperature coefllcient metal or alloy, and this voltage varies from one to several hundred percent, thereby providing a means or very sensitive ad- Justment. The high temperature coefllcient metal may be of the same size as that of the heating element, or may be smaller or larger as may be desired in order to obtain the desired result.

The voltages across the high temperature metal may also be used to indicate temperature, as it may be connected to a volt meter calibrated in degrees, so that the device would be adapted for use for ovens, furnaces, or other devices where correct temperature is imperative.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A temperature control device, particularly adapted for electrically heated appliances, comprising a circuit breaker remotely situated from the body 01' the appliance, and means controlling the operating circuit of said circuit breaker comprising a piece of material having a high temperature coeflicient of resistance in series with a heating element in said appliance, said high temperature coeflicient unit adapted to increase the electromotive force of the said circuit breaker as the temperature of the body 01' the appliance increases, and substantially in proportion to the increase 01' the temperature thereof, and means adjusting said circuit breaker to maintain a substantially even temperature in the body of said appliance; said circuit breaker having a bimetal element influenced by a coil in parallel with the metal having a high temperature coeflicient of resistance.

2. A device, as described in claim 1, characterized in that the electric supplying circuit is connected directly to one terminal of the heating element at one point, and to the opposite terminal of the heating element through the said circuit breaker, and the high temperature coeflicient material is connected at one end to the terminal of the heating element through which the supply current passing through the circuit breaker is connected and to the operating circuit of the circuit breaker at the other end, thereby being in series with the said heating element.

3. A control unit for'devices electrically heated, comprising a thermostat in the circuit of the said device, and a unit oi! material having a high temperature coefficient of resistance connected in series with the heating element of the said device and positioned to be influenced thereby, and also connected in parallel with the operating circuit of the said control unit, and adapted to intermittently operate said unit to make and break the circuit with a pulsating action dependent upon the temperature of the said device.

4. A control device, as described in claim 3, characterized by adJusting means for the said control unit adapted to set the unit to maintain a substantially even temperature in the said device.

ALVIN H. WAAGE. 

